%0 Journal Article %A Ya. Ihara %T On discrete subgroups of the two by two projective linear group over $\mathfrak p$-adic fields %J Matematika %D 1968 %P 98-115 %V 12 %N 3 %I mathdoc %U http://geodesic.mathdoc.fr/item/MAT_1968_12_3_a2/ %G ru %F MAT_1968_12_3_a2